Reductive stripping process for the recovery of either or both uranium and vanadium

Abstract

A process for the reductive stripping of an organic phase containing either or both uranium and vanadium. Said process comprising contacting said organic phase containing either or both uranium in the hexavalent state and vanadium in the pentavalent state with an aqueous solution containing a predetermined quantity of trivalent vanadium to reduce either or both the uranium and vanadium to a lower valence state which is not soluble in said organic phase. The reduced uranium and vanadium separate from the organic phase and collect in the aqueous solution from which it may be subsequently recovered. The process of this invention yields an aqueous strip solution containing fewer contaminates comprising undesirable alkali metals such as sodium and the like than other known chemical stripping processes. Further, the process limits the quantity of ferrous ions present in the system to alleviate the problem of sludge formation in subsequent treatment of the wet process acid to produce phosphate fertilizer.

What is claimed is: 
     
       1. A process for recovering at least one specie selected from the group consisting of hexavalent uranium and pentavalent vanadium from wet process phosphoric acid comprising contacting said wet process phosphoric acid with an organic extractant dissolved in a substantially water immiscible organic diluent to separate the selected specie from the wet process phosphoric acid, disengaging the organic extractant from the wet process phosphoric acid and then contacting the organic extractant with a stripping solution to separate the extracted specie from the organic extractant for recovery, the improvement which comprises providing a stripping solution comprising a phosphoric acid solution containing trivalent vanadium in which the trivalent vanadium is used to reduce the extracted specie to a lower valence state to effect the separation from the organic extractant. 
     
     
       2. The process of claim 1 in which the stripping solution contains from about 10 to about 60 grams trivalent vanadium as V 2  O 5  per liter. 
     
     
       3. The process of claim 1 in which the stripping solution comprises a phosphoric acid solution having a concentration of from about 20 percent to about 70 percent acid as P 2  O 5 . 
     
     
       4. The process of claim 1 in which the stripping solution comprises a phosphoric acid solution having a concentration of from about 25 percent to about 35 percent acid as P 2  O 5  and containing from about 10 to about 30 grams trivalent vanadium as V 2  O 5  per liter. 
     
     
       5. A process comprising: contacting an organic extractant containing at least one specie selected from the group consisting of hexavalent uranium and pentavalent vanadium with a stripping solution comprising a phosphoric acid solution containing trivalent vanadium in which said trivalent vanadium is present in an effective amount to reduce at least a portion of the specie selected from the group consisting of hexavalent uranium and pentavalent vanadium contained in the extractant to a lower valence state to cause said reduced specie to separate from the organic extractant; and   recovering the stripping solution containing the specie separated from the organic extractant.   
     
     
       6. The process of claim 5 in which the phosphoric acid concentration of the stripping solution is from about 20 percent to about 70 percent acid as P 2  O 5 . 
     
     
       7. The process of claim 5 in which the phosphoric acid concentration of the stripping solution is from about 25 percent to about 35 percent acid as P 2  O 5 . 
     
     
       8. The process of claim 5 in which the stripping solution contains from about 10 grams to about 60 grams of trivalent vanadium as V 2  O 5  per liter. 
     
     
       9. The process of claim 5 in which the organic extraction contains hexavalent uranium and pentavalent vanadium and contacting the organic extractant with an effective amount of trivalent vanadium is defined as: contacting the organic extractant containing hexavalent uranium and pentavalent vanadium with a first portion of a stripping solution containing trivalent vanadium in which said trivalent vanadium is present in an effective amount to reduce at least a portion of the vanadium specie contained in the organic extractant and then contacting the organic extractant with a second portion of the stripping solution in which the trivalent vanadium is present in an effective amount to reduce at least a portion of the uranium specie contained in the organic extractant.